to extemporise

listen to the pronunciation of to extemporise
Английский Язык - Английский Язык
To make or create extempore
To do something, particularly to perform or speak, without prior planning or thought; to act in an impromptu manner; to improvise
To do something in a makeshift way
{f} do something (i.e. sing, perform, speak) without advance preparation, improvise (also extemporize)
To compose extemporaneously or improvise